Working principle of thermocouples
Thermocouples operate based on voltage signals rather than resistance signals
Correct conclusion:
A thermocouple with a normal resistance value is not necessarily a thermocouple that can work properly, but a thermocouple with an abnormal resistance value is definitely a damaged thermocouple.
Many people think:
Use the resistance range of a multimeter to test the thermocouple to determine its quality.
Thermocouple: It is a sensor that converts temperature changes into electrical signals.
The temperature made using the Seebeck effect The sensor is called a "thermocouple". Seebeck effect: When two different metal wires are connected, a temperature difference is created at both ends of the connection, resulting in the generation of voltage.
① Two different metals
② There is a temperature difference
Working diagram of thermocouple measuring instrument
Illustration of the temperature measurement principle of thermocouples
Suppose the ice-water mixture is replaced with normal-temperature water. What would be the result of the voltage?
Hot runner analogy
Think: Sort the signal sizes of the millivoltmeter in the following four figures
